class Point {
  num x;
  num y;
  num z = 0;

  Point(this.x, this.y);
  //Point(num x, num y) {
  //  this.x = x;
  //  this.y = y;
  //}

  //named constructor
  Point.origin() {
    this.x = 0; //this可以省略
    this.y = 0;
  }
}

main() {
  var p = new Point(23, 34);
  print(p.x);

  var p2 = new Point.origin();
  print(p2.x);
}
//EOP
